GIS stands for Geographic Information Systems, but the “S” is increasingly being used to stand for science and studies as well. Geographic Information Science, and Geographic Information Studies are used increasingly. No universally agreed-upon definition has been put forth. Surprisingly, a number of GIS texts do not even attempt to define the term.
Traditionally, GIS is a computer-based system for collecting, managing, analyzing, modeling, and presenting geographic data for a wide range of applications.
Geographic Information Science, then, is the discipline that studies and uses a GIS as a tool. GIS is not simply creating maps with a computer. The technology is a very powerful tool for analyzing spatial data; while maps can be and are produced with GIS, their main power is analytical.
GI scientists do not consider themselves primarily as mapmakers. Although they may produce maps as an end product, their primary emphasis is on analysis of the data. In fact, it is comparatively recently that GI systems people have given much thought to presentation of data.
Edited from: Tyner, J. (2010). Principles of Map Design. The Guilford Press.